Therapeutic tubs, commonly called "spas," have become increasingly popular in recent years. Certain of such spas are formed of a relatively rigid plastic, such as Fiberglas, and have a plurality of nozzles mounted in the walls to project high velocity, massaging streams of water against occupants of the tub. As in the case of swimming pools, such spas require periodic cleaning, and it would be highly desirable to be able to effect such cleaning by a vacuuming device. However, there is no convenient way of attaching a vacuum hose to the suction side of the spa circulating pump.